Furnace for boilers.



R. P. STURROCK.

FURNACE FOR BOILERS.

APPLIOATION FILED Mia-11.12 1912.

1,103,098. Patented July 14, 1914,

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FURNACE FOR BOILERS.

APPLICATION FILED MAR. 12, 1912.

1,103,098. 7 Patented July 14, 1914.

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WITNESSES;

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W 49% 9 MM .MQMWM h ROBERT FINDLAY STURROGK; or DUNDEE, SCOTLAND.

FURNACE FOR BOILERS.

Specification of Letters Patent.

Patented uly 14, 1914.

Application filed March 12, 1912. Serial No. 683,353.

To all whom it may concern Be it known that I, ROBERT FINDLAY SrURRooK, a subject of the King of Great Britain and Ireland, residing at 41 Reform street, Dundee, in the county of Forfar, Scotland, have invented new and useful Improvements in Furnaces for Boilers, of which the following is a specification.

This invention relates to furnaces for boilers and is an improvement on the type of furnace which has been described in my prior British Patents Nos. 17940 of A. D. 1901 and 8047 of A. D. 1907.

My invention consists in improved construction of furnace bridges of this type and more particularly in the method of holding the bars in position without the aid of bolts each bar forming a complete arch with both ends resting on the foundation plate.

In order that my said invention and the manner of putting the same into practice may be properly understood, I have here unto appended two explanatory sheets of drawings in which the same reference numerals are .used to indicate corresponding parts in the figures shown.

Figure 1 is a sectional elevation of the furnace of a marine boiler showing the bridge. Fig. 2 is a section through the furnace and looking on the bridge in the direction of the arrow A (Fig. l) and showing a portion of the bars removed. Figs. 3 and 4 are modified views of Figs. 1 and 2 show ing how the air supply to the bridge can be regulated.

The invention, when used in connection with natural draft (as in Figs. 1 and 2) consists in the use of a foundation plate 1 which is placed across the furnace 2 with openings 3 at the top and closed at the back and provided with the usual means for supporting the back ends of the furnace grate bars 4. The bridge proper consists of a series of bars 5 each bar being in one piece in the form of an inverted U with rounded top forming an arch, the front foot of each bar although free to expand or contract resting on the front and the back foot. resting on the back of the foundation plate, the hollow of the arch being over the apertures 3 in the foundation plate, and the bars held in position without the aid of bolts, 12 being an interlocking projection fitting into a corresponding recess in the adjacent bar.

The part of the foundation plate 6 where the back feet of the bridge bars rest on it is in some cases channeled (see Fig. 3) and the interior side of this channel has a ledge 7 which projects over the feet of all the bars except one, so that when the bars are in position they cannot be lifted off the foundation plate except at the opening 17. The bars are removed or replaced by sliding each to the point 17 where there is no ledge and then lifting it out.

In Figs. 1 and 2 the bars are recessed at 6 that is instead of being kept in position by resting in a channel as in the other figures they are retained in position by a ridge. Each bar is made with a thickened edge 8 and thin web 9 on the underside and suitable recesses 10 are made in the sides of each thickened edge at the front and sloping part, or at the crown, so that when the bars are in position, air passages are formed by these recesses. The back portion of the bars are preferably vertical as in Figs. 1 and 3 and there are no apertures there, and the thickened edges may have grooves 11 so arranged that when the bars are in position asbestos cord or gannister'may be placed between them to insure that no air can pass.

In Figs. 3 and 4 the foundation plate is shown with a hinged door 13 which can be made to open or close against a plate 14 by means of the handle 15, the arrangement being used where it is desired to regulate the supply of air to the bridge in conjunction with natural induced or forced draft. I make no claim to the use of a regulator of this type as I have used it before in connection with my prior patents.

Having now described my invention, what I claim as new and desire to secure by Letters Patent is In a furnace bridge, in combination, a plate provided with a horizontal uppersurface, and a plurality of inverted U-shaped bridge bars arranged side by side and having their lower ends engaging said plate, the front limbs of said bars being provided with air passages, the rear limbs of said bars being free from air passages, the rear limbs of said bars and said plate being provided with co-acting locking means to hold said rear limbs against movement transversely of said plate, the front limbs of said bars and said plate being free from co-acting locking Q 5 tions engaging the recesses of adjacent bars means, whereby said front limbs are free to name to this specification in the presence of move transversely of said plate, each of said two subscribing witnesses.

bars being provided with a lateral recess and a laterally extending projection, the p'rojec- WROBERT FINDLAY STURROGK' itnes'ses:

GEORGE CAMERON DOUGLAS, AGNES OULBARD DOUGLAS.

to lock the bars together. i y

In testimony whereof I have signed my Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, .D. 0. 

